PL/SQL Numeric error in calling proc from VB5-ADO

I am calling a proc within a package from VB5 using ADO and the Microoft ODBC for Oracle driver.
The proc checks a users Oracle roles for security checking. The proc runs fine for weeks on end but then suddenly returns the Oracle error: "PL/SQL or Numeric error" upon someone accessing it. All subsequent calls to it receive the same error and all connections are locked. The proc can be run through SQLPlus without a problem. The database must be recycled to free it. I am reusing the connection object for the entire session, is this a problem?.
Has anyone encountered this message before? Am I exceeding an Oracle connection limitation? ADO limitation?

Thanks in advance! Received on Wed Aug 30 2000 - 08:18:47 CDT